Collapsible mandrel for hollow piles



Feb. 2, 1965 BARCUS ETAL 3,167,924

COLLAPSIBLE MANDREL FOR HOLLOW FILES Filed March 13, 1959 2 Sheets-Sheet 2 50 Fly. 6

Lawrence 6. Baraus William R. Barcus INVENTORS BY WW 5% United States Patent 3,167,924 COLLAPSIBLE MANDREL FOR HOLLOW FILES Lawrence G. Barcus, 1877 Praun Lane, and William R. Barcus, 2001 New Jersey, both of Kansas City, Kans. Filed Mar. 13, 1959, Ser. No. 799,278 9 Claims. (Cl. 6153.72)

This invention relates in general to new and useful improvements in the art of driving piles, and more specifically to an improved collapsible mandrel for-use in driving hollow piles.

In the formation of concrete piles, hollow pile elements in the form of metal pipes having driving noses on the lower ends thereof are first driven into the ground to the desired penetration after which they are filled with concrete. Inasmuch as the metal pipes merely form a casing for the concrete, it is desirable that they be formed as light as possible although they must have sufficient rigidity to be driven to the desired penetration. For that reason, it is necessary that a mandrel be placed in the pile elements to give them the necessary rigidity while being driven.

One of the primary difiiculties in driving piles with a mandrel is to obtain the necessary interlock between the mandrel and the pile element for driving purposes and at the same time facilitate the removal of the collapsible mandrel from the pile element when the pile has been driven. It is therefore the primary object of this invention to provide a collapsible mandrel for hollow piles, which mandrel is so constructed that it may be collapsed to the point where it may be easily entered into a hollow pile element and a portion thereof anchored to the hollow pile element so that when force is applied on the upper end of the mandrel, the mandrel will expand and properly engage the hollow pile element for driving the same.

Another object of this invention is to provide a col lapsible mandrel for hollow pile elements of readily available material of an inexpensive type whereby the collapsible mandrel may be manufactured at a very low cost as compared to other types of mandrel.

Another object of this invention is to provide a collapsible mandrel for hollow pile elements formed in two sections, the sections having a plurality of interengaging cam members, the cam members having sloping surfaces whereby as one of the mandrel sections is moved relative to the other of the mandrel sections, the collapsible mandrel is either collapsed or expanded depending upon the relative direction of movement.

A further object of this invention is to provide a collapsible mandrel for driving hollow pile elements, the collapsible mandrel including a plurality of Wedge members which are so related that as the collapsible mandrel has pressure applied axially thereto, the mandrel sections will diametrically expand, and one of the mandrel sections having lift means thereon so that when the one mandrel section is lifted, the mandrel sections will retract towards each other so as to collapse the mandrel.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawing forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a vertical sectional view taken through a hollow pile element which has been driven into the ground and shows the relationship of the collapsible mandrel with respect thereto in the driving position, intermediate portions of the hollow pile element and the collapsible mandrel being omitted;

FIGURE 2 is a sectional view similar to FIGURE 1 and shows one of the sections of the collapsible mandrel elevated so as to collapse the mandrel for removal from the hollow pile element;

FIGURE 3 is a horizontal sectional View taken substantially upon the plane indicated by the section line 33 of FIGURE 1 and shows the relationship of the mandrel sections of the collapsible mandrel with respect to the hollow pile element when the collapsible mandrel has been expanded into driving engagement with the hollow pile element;

FIGURE 4 is a horizontal sectional view taken substantially upon the plane indicated by the section line 44 of FIGURE 2 and shows the relationship of the sections of the collapsible mandrel when the mandrel has been collapsed to removal from the hollow pile element;

FIGURE 5 is a perspective view of one of the mandrel sections and shows the general details thereof, an intermediate portion of the mandrel section being omitted; and

FIGURE 6 is a perspective view of the other of the mandrel sections and shows the details of that mandrel section, an intermediate portion of the mandrel section being omitted.

Referring now to the drawings in detail, it will be seen that there is illustrated in FIGURE 1 a hollow pile element which is referred to in general by the reference numeral 10. The hollow pile element 10 is formed of a section of pipe or casing 12 which is provided at the lower end thereof with a driving nose 14 to facilitate the driving of the hollow pile element 10 into the ground 16. Once the hollow pile element 10 has been driven into the ground, it is then filled with concrete so as to form a concrete pile. In order to facilitate the driving of the hollow pile element Ill into the ground 16, there is provided the collapsible mandrel which is the subject of this invention, the collapsible mandrel being referred to in general by the reference numeral 18.

The collapsible mandrel 18 is formed of a longitudinal pair of mandrel sections or segments 20 and 22 which are best illustrated in FIGURES 5 and 6, respectively.

The active mandrel section 20 includes a semi-cylindrical body or shell portion 24 which has secured to the edges thereof face plate forming members 26 and 28 which are disposed in spaced relation on opposite sides of an axis passing through the center of curvature of the body member 24. The space between the face plate forming members 26 and 28 is referred to by the reference numeral 30 and the face plate is referred to in general by the reference numeral 32.

The lower end of the mandrel section 20 is closed by a bottom plate 34, and the upper end thereof is closed by a top plate 36. The mandrel section 20 also includes driving means having a circular driving plate 38 which overlies the plate 36. In addition to this, extending transversely through the body member 24 and projecting through opposite surfaces thereof adjacent the upper end of the mandrel section 20 is a lifting rod 40.

Secured to the body member 24 and the base plate 32 is a plurality of wedge or cam members 42. The wedge members 42 have been illustrated as being in the form of cam plates although they :may be as wide as is deemed necessary. The wedge members 42, as is best shown in FIGURES 1 and 5, slope upwardly at an angle of approximately 30 and are in vertically spaced relation. The space between the wedge members 42 is substantially equal to the width of the wedge members 42. It is to be noted that the wedge members 42 project outwardly from the face plate 32 a distance perpendicular thereto, substantially equal to the inner radius of curvature of the semi-cylindrical body member 24.

The passive mandrel section 22 is of a very similar in FIGURE 6. The mandrel section 22 also includes a semi-cylindrical body member 44 which has secured to the edges thereof face plate forming members 46 and 48 which combine to form a face plate which is referred to in general by the reference numeral 50. The face plate forming members 46 and 48' are spaced apart on opposite sides of the axis of curvature of the body mom: her 44 to define a space 52. The lower end of the mandrel section 22 is closed by a plate 54. A similar plate 56 closes the upper end of the mandrel section 22.

Secured to both the body member 44 and the face plate 50 is a plurality of downwardly sloping wedge members 58. The wedge membersSS slope downwardly at an angle of approximately 30 and are in the form of narrow plates although they may be of any desired width. The wedge members 58 project outwardly from the face plate 50 a distance perpendicular thereto, approximately equal to the inner radius of curvature of the semi-cylindrical body member 44.

It is to be noted that the wedge members 58 are vertically spaced with respect to each other a distance substantially equalto the vertical width of the Wedge members 58. From practice, the spacing between the wedge members 42 is equal to the width of the wedge members 58, and the spacing between the wedge members 53 is equal to'the width of the wedge members 42. Thus the mandrel sections and 22 may be interlocked by sliding the wedge members 42 through the space 52 between the wedge members 58 with the wedge members 58 pass ing between the wedge members 42 and into the space in the base plate 32.

In order that the mandrel section 22 may be. temporarily fixed against movement relative to the hollow pile element 11), the lower part of the body member 44 is provided with a plurality of ribs 60 or similar projections. When the collapsible mandrel 18 is placed in the hollow pile element 10, the ribs engage the lower part of the inner surface of the pipe 12 and resist movement of the mandrel section 22 relative to the pipe 12. Then as pressure is applied to the driving plate 38 to move the-mandrel section 20 downwardly, the mandrel section 26} moves downwardly with respect to the mandrel section 22. This results in the outward movement of the mandrel section 219 relative to the mandrel section 22 due to the mating sloping surfaces of the wedge members 4-2 and 58. It is preferred that the collapsible mandrel 18 be designed for a particular size of hollow pile elements 11). Thus when the driving plate 38 engages the plate 56, the mandrel sections 20 and 22 will have expanded into the desired engagement With the pipe 12 of the hollow pile element 10, as is shown in FIGURE 1. The hollow pile element 10 may then be driven to the point of penetration, which is illustrated in FIGURE 1.

After the hollow pile element 10 has been driven to the desired penetration, it is then necessary that the collapsible mandrel 13 be removed therefrom so that concrete may be poured into. the hollow pile element 10 to complete the concrete pile. This is accomplished by placing suitable lifting means on the pin andexerting an upward force on the mandrel section 20. Inasmuch as the mandrel section 22 is temporarily locked against upward movement with respect to the pipe 12, it will be seen that the mandrel section 20 will move upwardly. This will result in the collapsing of the hollow mandrel 13 to the position illustrated in FIGURE 2 so that it may be readily removed from the hollow pile element 11).

As is best illustrated in FIGURE 3, it will beseen that the [face plate forming members 26 and 28 may ac tually be in the form of angle bar members so as to provide a suitable guide for the wedge members 58 of the mandrel section 22. Likewise, the face plate forming members 46 and 48 are also in the form of angle members so that the hidden flanges thereof may form guides for the wedge members 42. This arrangement will also preventtwistingof the mandrel sections 2% and 22 relative to each other.

From the foregoing description of the collapsible mandrel 18, it will be seen that the construction thereof is such that the operation is assured. On the other hand, it will also be readily apparent that the collapsible mandrel 18 is formed of readily obtainable materials which are commercially produced in large quantities so as to be relatively inexpensive. Thus the cost of the collapsible mandrel 18 is relatively small, as compared to the cost of other types of collapsible mandrels.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown'and described, and accordingly, all suitable modifications and equivalents may be resorted to,falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A collapsible rnandrel for a hollow pile comprising a pair oflongitudinally extending mandrel sections, said mandrel sections having outer surfaces engageable'with said pile and opposed face plates, a plurality of longitudinally spaced wedge members extending from;each of said face plates inwardly spaced from the outer surfaces,

said wedge members all lyingin a common longitudinal plane and having mating edge surfaces parallel to each other and sloping at an angle to theopposed face plates, the wedge members of one of said mandrel sections being interfitted with and complementing the wedge members of the other of said mandrel sections whereby as one of said mandrel sections is moved relative to the other of said mandrel sections the spacing between said face plates varies and driving means connected to said one of the mandrel sections for directly transmitting 'for'ce thereto in a direction parallel to said common longitudinal plane.

2. A collapsible mandrel. for hollow piles comprising a pair of longitudinally extending mandrel sections, said mandrel sections having opposed face plates, a plurality of longitudinally spaced wedge members extending from each of said face plates, said wedge members all lying in a common longitudinal plane and having mating edge surfaces parallel to each other and sloping downwardly and upwardly at, an angle to, the opposed face plates, the wedge members of one of said mandrel sections being interfitted with and complementing the wedge members of the other of said mandrel sectionswhereby as one of said mandrel sections is moved relative to the other of said mandrel sections the spacing between said face plates varies, each of said face plates having openings therein receiving the wedge members of the other of the mandrel sections whereby the collapsible mandrel may be collapsed to a position where said face plates are disposed in face abutting relation.

3. The combination of claim 1 wherein, each of said mandrel sections includes a semi-cylindrical body hearing saidouter face secured to a respective one of said face plates.

4. The combination of claim 1 wherein, said wedge members of one of said mandrel sections have upper and lower edge surfaces sloping upward and said wedge members of the other of said mandrel sections have upper and lower surfaces sloping downwardly.

5. The combination of claim 1 including, pile engaging means on the outer surface of said othermandrel section to fix said other mandrel section relative to the pile while said one mandrel section is moved relative to said other mandrel section by the driving means;

6. The combination of claim 1 wherein said driving means includes a driving plate on the upper end of said one mandrel section overlying said other mandrel section.

7. The collapsible mandrel as defined in claim 1, wherein each face plate has means for guidingly receiving the wedge members extending from the other face plate to prevent angular displacement between said mandrel sections.

8. In combination with a hollow pile casing adapted to be driven downwardly along the longitudinal axis thereof, an expansible mandrel unit comprising, at least two longitudinal sections each having a continuous outer shell portion engageable with the casing for transmitting force thereto in a direction parallel to said longitudinal axis, cam members secured to each of said sections inwardly spaced from the outer shell portion, the cam members on the respective sections having coacting surfaces inclined with respect to said longitudinal axis for radial displacement of the sections relative to said axis in response to relative movement between said sections parallel to said axis, guide means mounted on said sections and coacting to maintain a predetermined angular orientation of said sections relative to each other about said axis for all radial positions to which said sections are displaced, and means connected to one of said sections for transmitting movement thereto relative to the other section in said direction parallel to the longtudinal axis, said guide means comprising, opposed surfaces fixedly mounted on the respective sections from which the cam members extend, and means provided by said opposed surfaces for maintaining the opposed surfaces substantially parallel for all radial positions of the sections relative to the longitudinal axis, whereby coaction between the inclined surfaces of the cam members is assured and the outer surface portions of the sections maintained generally parallel to the internal surface of the hollow casing when engaged therewith.

9. In combination with a hollow pile casing adapted to be driven downwardly along the longitudinal axis thereof, an expansible mandrel unit comprising, at least two elongated sections, each section having an outer shell portion engageable with the casing for transmitting force thereto in a direction parallel to said longitudinal axis, elongated angle bars fixedly secured to the shell portions of the elongated sections presenting opposed surfaces on opposite sides of the longitudinal axis, a plurality of cam plates secured to the angle bars in longitudinally spaced relation to each other inclined at an angle to the opposed surfaces on one of the sections having parallel upper and lower edges sloping upwardly and interfitted between parallel coacting edges of cam plates on the other section sloping downwardly, and means connected to an upper end portion of one of said sections for transmitting movement thereto in said direction parallel to the longitudinal axis relative to the other section to cause said coacting edges to radially displace the sections relative to the longitudinal axis, at least one of the cam plates on one of the sections extending between the angle bars on the sections for guidingly maintaining relative angular orientation of the sections about the longitudinal axis for all positions to which the sections are radially displaced.

References Cited by the Examiner UNITED STATES PATENTS 589,026 8/97 Raymond 61-53.52

707,987 8/02 Torrey 254-42 1,403,766 1/22 Gillies 61-5372 2,246,509 6/41 Davies 20-924 2,871,666 2/59 Pickman 6153.72 2,916,224 12/59 Larsen 242--72.1 2,928,252 3/60 McKee 61-53.72

FOREIGN PATENTS 1,068,306 1954 France.

JACOB L. NACKENOFF, Primary Examiner.

WILLIAM I. MUSHAKE, JACOB SHAPIRO,

Examiners. 

1. A COLLAPSIBLE MANDREL FOR A HOLLOW PILE COMPRISING A PAIR OF LONGITUDINALLY EXTENDING MANDREL SECTIONS, SAID MANDREL SECTIONS HAVING OUTER SURFACES ENGAGEABLE WITH SAID PILE AND OPPOSED FACE PLATES, A PLURALITY OF LONGITUDINALLY SPACED WEDGE MEMBERS EXTENDING FROM EACH OF SAID FACE PLATES INWARDLY SPACED FROM THE OUTER SURFACES, SAID WEDGE MEMBERS ALL LYING IN A COMMON LONGITUDINAL PLANE AND HAVING MATING EDGE SURFACES PARALLEL TO EACH OTHER AND SLOPING AT AN ANGLE TO THE OPPOSED FACE PLATES, THE WEDGE MEMBERS OF ONE OF SAID MANDREL SECTIONS BEING INTERFITTED WITH AND COMPLEMENTING THE WEDGE MEMBERS 